Forming display color image

Abstract

An apparatus for forming a colored image on a display, includes a VCSEL array device having a plurality of light-emitting pixels wherein each light-emitting pixel produces a beam of light including substantial components in a portion of the visible spectrum so that different light-emitting pixels produce different colored light; and a light shutter layer for each light-emitting pixel providing a modulator disposed in the path of the corresponding light beam for selectively passing corresponding colored light for providing a colored light image on the display.

Description

CROSS REFERENCE TO RELATED APPLICATIONS [0001] Reference is made to commonly assigned U.S. patent application Ser. No. 10 / 857,508, filed May 28, 2004, by Keith B. Kahen and Erica N. Montbach, entitled “DISPLAY DEVICE USING VERTICAL CAVITY LASER ARRAYS”, and commonly assigned U.S. patent application Ser. No. 10 / 857,512 filed May 28, 2004 by Keith B. Kahen and Erica N. Montbach, entitled “VERTICAL CAVITY LASER PRODUCING DIFFERENT COLOR LIGHT”, the disclosures of which are herein incorporated by reference.FIELD OF THE INVENTION [0002] The present invention relates to forming a color image using a light source and a modulator. BACKGROUND OF THE INVENTION [0003] There are a number of ways of producing pixelated colored light for display applications, such as for example, using a conventional passive or active matrix organic light emitting diode (OLED) device. Another way is to employ a liquid crystal display (LCD). In typical LCD systems, a liquid crystal cell is placed between a pair of...

AI Technical Summary

Benefits of technology

[0013] It is an advantage of the present invention to use a pixelated two-dimensional vertical cavity surface emitting laser (VCSEL) array as the light source for a display. Each color element contains thousands of micron-sized laser pixels, which are mutually incoherent. This leads to each color element producing multimode laser light. As a result of the pixel size being 3 to 5 microns in diameter, the divergence angle of the multimode laser light is on the order of 3-5°. This small divergence angle enables a 1:1 correspondence between the laser's color elements and a suitable optical switch. Correspondingly, it is no longer necessary to include a color filter array as one of display film components.

Problems solved by technology

Correspondingly, this absorption of light outside of each pixel's transmission spectra results in a loss of overall display efficiency.

However, not all of the light of the undesired polarization is recycled and not all of the recycled light exits the BLU with the correct polarization state.

As a result, unpolarized BLU light results in nearly a factor of two efficiency loss upon passing through the bottom polarizer.

However, LCD's suffer from poor contrast ratios at larger viewing angles.

Unless the contrast ratio is improved at large viewing angles, the penetration of LCDs into certain markets will be limited.

The poor contrast ratio is typically due to increased brightness of the display's dark state.

However, these methods improve the hue shift and contrast ratio only slightly and for a limited viewing cone.

Also, the manufacturing of compensation films and multi-domain liquid crystal cells is typically expensive, thus increasing the overall cost of the display.

Also, the PL-LCD light source is much less efficient than the standard cold cathode fluorescent lamps (CCFLs) used in typical LCD displays.

As discussed above, these drawbacks are loss of efficiency (due to unpolarized backlights and usage of CFA's), poor color gamut, and loss of contrast and color at larger viewing angles.

OLED displays overcome some of these disadvantages, however, they currently suffer from short lifetimes and higher manufacturing costs.

Part of the higher manufacturing cost is inherent in the OLED design, such as the need to pixelate the OLED emitter region and the greater complexity of thin film transistors (TFTs) for current driven devices.

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